Logging practices can "greatly increase the severity of fires" in extreme weather conditions such as Black Saturday, Australian researchers have said.

Researchers from the Australian National University (ANU) and Melbourne University examined hundreds of thousands of trees burnt in the 2009 bushfires in Victoria, which claimed the lives of 173 people on a day of extreme temperatures and high winds.

They found that the increased fire risk began about seven years after an area had been logged and lasted for another 50 years.

Professor David Lindenmayer, from the ANU, said the results showed the fires around Kinglake and Marysville were about 25 per cent more severe due to the clear-felling of forest in the area.

"If we cut down a forest tomorrow, we're still going to be adding to the fire risk in 50 years time," he told 774 ABC Melbourne.

Professor Lindenmayer said the big concern was that many of the areas recently logged were around towns such as Healesville, Toolangi, Warburton, Noojee and Marysville.

"It's a really important outcome, and quite a concerning one, given how much logging has taken place in the last 40 years and how much logging is planned in the next five to 10 years," he said.

Professor Lindenmayer said there should be no logging within five to 10 kilometres of towns to ensure "that we don't add extra risk through extra logging".

"There's a need to comprehensively revise forest policy in this state to reduce fire risk," he said.

"We need to let those forests recover and we need to develop the wet forests... which do have a fire suppressive effect."